1. Field
The present disclosure relates to turbomachine structures, more specifically to systems and methods for managing the effects of thermal stress on turbomachine components.
2. Description of Related Art
It is common to have high stresses in full-ring or annular structures in turbomachines that are subjected to thermal gradients due to differences in expansion caused by the differences in local temperatures in the annular structure. If the stress issue is not addressed, fatigue cracks can initiate randomly around the circumference of the ring structure. A common method to address the stress problem is to “slot” completely through the thickness of the part, through some portion of the length thereof (radial or axial or both), to a location usually towards the middle of the part where stresses are low enough not to initiate fatigue cracks.
These slots may solve the stress problem and stop fatigue cracking, however, the problem with current methods of slotting is that conventional manufacturing processes will inherently leave a slot of a certain width (or gap), typically greater than 0.010″ wide, due to the width of the cutting tool or process (milling, grinding, sawing, wire electro-discharge machining, abrasive water jet, laser, plasma etc.). The resulting slot will then provide a leak path for gasses if there is any pressure difference across the thickness of the part. This leakage can be particularly undesirable if the higher pressure gas is needed elsewhere in the machine to provide cooling of other parts or components or result in a loss in efficiency.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved annular structures for turbomachines. The present disclosure provides a solution for this need.